how to install magic uv addon
First unzip the file. You'll have a folder with .py files in it.
Then go to the "scripts" folder in your blender installation directory.
In the "scripts" folder you'll find another folder named "addons". Open that.
Then copy the folder you have unzipped in to this "addons" folder.


You're done. Now all you need to do is open Blender and go to File -> User Preferences. Go to the "Add-ons" tab and search for it and it'll be there. Make sure the "Community" supported level is turned on.